1. Technical Field
This invention generally relates to ratchet assemblies for use with rotationally biased take up reels, spools or shafts, and more particularly to a ratchet assembly wherein a pawl gear is released from engagement or held in engagement, with the spool shaft pawl gear by means of a mechanically driven ratchet gear.
2. Background
In its most basic format, the ratchet assemblies used in the prior art are typically configured to include a ratchet gear attached to a spring loaded shaft, and a pawl attached to a stationery housing and spring loaded to engage with the teeth of the ratchet gear so as to permit rotation of the ratchet gear in one direction and prohibit rotation in the other by engagement with a tooth of the ratchet gear. The release mechanism for the pawl is typically, in the prior art, either a mechanical release mechanism typically including some sort of a handle operable by the operator to lift the pawl gear out of engagement with the ratchet gear, or some sort of a centrifugal force mechanism to hold the pawl out of engagement with the ratchet gear when the pawl gear and the shaft are being rotated quickly. For example, the mechanism found on the common window shade is usually a centrifugal force mechanism.
Common examples of these prior art configurations are found in: U.S. Pat. No. 2,530,773 to Johnson et al.; and U.S. Pat. No. 2,698,146 to Becker, as well as all of the other cited prior art.
All of these suffer from the same limitations, in that they either must have some sort of manual release mechanism for holding the pawl out of engagement with the ratchet gear, or the rotational speed of retraction of the spring loaded spool must be sufficiently fast to induce sufficient centrifugal forces to hold the pawl out of engagement.
What is needed is a mechanically driven ratchet assembly which automatically induces rotational motion in a ratchet gear to permit withdrawal of line or cordage from the spool to either a locked position or a retraction position without the need for any manual release mechanism or centrifugal force to overcome the engagement of a spring loaded pawl with a ratchet gear.